This invention relates to a method for sealing the air hole in concrete forms.
Reusable concrete forms are sometimes provided with an air hole in the upper face of the form for facilitating removal of the form. After the concrete which was poured on the form partially sets, air is blown under pressure through the air hole to provide a layer of pressured air between the top of the form and the concrete. This pressured air shoves down the form by a small amount, which frees the form or loosens it enough to make freeing of the form easier. In using the concrete form, it is necessary to seal the air hole so that concrete does not leak through it before the concrete sets. various devices such as tape have been utilized to seal the air hole, but these have not been entirely satisfactory. The sealing device must be capable of rapid application and should be strongly enough held to prevent collapse under the weight of concrete while permitting reverse air flow during loosening, and it should permit an even distribution of air onto the upper face of the form in all directions from the air hole. Furthermore, a definite indication should be provided as to whether the device has been securely installed. An economical device that could securely seal the air hole and provide a definite indication as to whether it was properly installed, and which encouraged a uniform distribution of pressured air during release of the form, would facilitate the use of concrete forms.